The invention is directed towards the field of electronic circuitry, and more specifically, towards ergonomic input devices such as a computer mouse.
Repetitive Strain Injuries (RSI) are a modern-day hazard in the computer-using workforce, and are a leading cause of occupational injuries in the United States today. Computer mouse usage is blamed for many of these injuries. A mouse is typically used as an input device that controls the movement of a cursor or other display element on a display screen. The conventional and most commonly used mouse resembles a bar of soap in shape and size. This xe2x80x9csoap barxe2x80x9d mouse is designed such that a user""s palm and fingers rest on the mouse body when moving the mouse or activating its buttons. Unfortunately, this design requires the user""s fingers to be splayed out over the mouse body and buttons, instead of being slightly curled in as is natural when the hand is relaxed. Furthermore, the hand is completely pronated (rotated so that the palm faces down, parallel to the desk top) while working the mouse. This unnatural position strains the tendons in the hand, and can be harmful especially when maintained for an extended period of time. A more natural and ergonomic position for the hand is one where the palm and wrist are 45xc2x0 to 90xc2x0 less twisted. Finally, the primary switch on a conventional mouse is designed to be activated by a tap of the forefinger. However, this requires the forefinger to be flexed repeatedly while the hand is pronated. This motion can strain the finger tendons.
Many computer pointing devices have ergonomic features that strive to minimize user discomfort. For instance, a joystick mouse is gripped like a vertical bicycle handle, which keeps the palm perpendicular to the desktop and the fingers curled in. However, it is difficult to control a joystick with the high degree of accuracy required by many Computer-Aided Design (CAD) tools, since a joystick is manipulated with hand and arm muscles that are better suited to gross motor movement than to fine motions.
A tablet and stylus combination, such as the ones made by Wacom Technology Co., offers the user more control, precision, and accuracy. The stylus is held like a pen, and the dexterous finger muscles have great control over the stylus. Additionally, the hand remains in a natural and relaxed position. Unfortunately, the stylus must be used with a special surface such as the tabletxe2x80x94it will not work when used on a desktop. Also, the primary switch mechanism usually involves tapping the stylus against the surface of the tabletxe2x80x94again, this will not work on an ordinary desktop. Furthermore, the pen must be picked up each time it is to be used, which is a repetitive inconvenience.
Finally, in U.S. Pat. No. 6,151,015 to Badyal et al (assigned to Agilent Technologies) a pen-like computer pointing device is disclosed that uses an optical sensor to scan a work surface. Although the pointing device is an ergonomic, working solution, it must be picked up with each use. Furthermore, the pointing device is sensitive to the angle at which it is held, since the optical sensor contained within requires the pointing device to be held at a certain angle. If the pointing device is tilted beyond the narrow range of the optical sensor, the pointing device stops functioning. Also, the optical sensor within the pointing device must be oriented in the same direction during use, requiring the user to rotate the pointing device to the correct orientation before each use. Finally, the primary switch mechanism employed by the pointing device is a button on the body of the device, which still requires a tap of the forefinger and can strain the finger tendons if used repetitively.
Consequently, there remains a need for an ergonomic computer pointing device that does not need to be picked up before each use, has accurate positioning capability and an improved switch mechanism, while allowing a user""s hand to remain in a natural, relaxed position.
The general idea for the present invention was partially derived by observing the writing process. Writers use an inherently ergonomic hand position, hereinafter referred to as the writing position: the fingers remain curled, not splayed out; the hand is angled between 45 degrees and 90 degrees to the work surface, never completely pronated. Additionally, the number of RSI cases associated with writing is relatively low, compared to the number of computer-related RSI cases. Therefore, it is logical and reasonable for an ergonomic mouse to recreate the hand positions and motions used in writing.
In accordance with an illustrated preferred embodiment of the present invention, an ergonomic mouse-pen is designed to be held in the writing position and manipulated like a writing implement. The mouse-pen is in communication with a computer or other instrument having a display screen. The mouse-pen has an elongated, cylindrical rod that is grasped in the fingers like a pen, enabling fine motor control for accuracy in placement of the mouse. The cylindrical rod is flexibly coupled to a weighted base so the mouse-pen remains upright and freestanding and does not need to be picked up before each use. The cylindrical rod can be shaped to have facets along its body for the user""s fingers to rest upon. This helps the user to automatically and effortlessly make any slight orientation corrections each time the user grasps the mouse-pen.
A relative motion sensor is installed in the base of the mouse-pen. The relative motion sensor senses movement of the mouse-pen and translates the movement into corresponding movement of a pointer, cursor, displayed element, or other object on the display screen. The relative motion sensor can be an optical sensor, although a mechanical ball bearing mechanism (such as the kind used in conventional mice) may be used if the ball bearing mechanism is small enough. If the relative motion sensor used is an optical sensor, the base keeps the optical sensor at a constant angle to the work surface and prevents undesirable tilting.
A primary switch is located at the juncture between the body and the base. The primary switch is activated by a downward motion on the body, as if the user were pressing a ball-point pen harder into a sheet paper. The entire weight of the hand is used in bearing down to actuate the primary switch, avoiding the painful motion of flexing just the forefinger alone. One or more optional secondary switches can be located in the body of the mouse-pen. The switches are typically activated to make a selection of an object or group of objects on the display screen, or to bring up a new menu.
In an alternate embodiment of the present invention, an ergonomic mini-mouse has a small body designed to be gripped between the thumb and the first two or three fingers of the hand. This allows the hand and fingers to remain in the natural and relaxed writing position. The small size of the mini-mouse serves primarily to facilitate dexterous use and control by the fingers, the same way one uses a pencil. Since deft finger muscles control the mini-mouse, it is possible to position the mini-mouse very accurately. Furthermore, the small size of the mini-mouse is well suited to the limited amount of space associated with laptop computers.
The mini-mouse is also inherently freestanding by designxe2x80x94there is no need to pick up the mini-mouse before each use. Switches are installed on the bottom of the mini-mouse, to be activated by a downward press against the work surface. For example, bearing down on the mini-mouse body towards the left actuates a left-sided switch; bearing down to the right actuates a right-sided switch. The entire weight of the hand is used to bear down on the mini-mouse to actuate these switches.
Further features and advantages of the present invention, as well as the structure and operation of preferred embodiments of the present invention, are described in detail below with reference to the accompanying exemplary drawings. In the drawings, like reference numbers indicate identical or functionally similar elements.